As indicated in U.S. Pat. No. 5,156,114, there is a need for fuels to replace diesel fuel and gasoline for use in internal combustion engines, especially engines used in motor vehicles. Internal combustion engines, such as engines operating on gasoline and diesel fuel, produce unacceptably high amounts of pollutants which are injurious to human health and may damage the earth's atmosphere. The adverse effects of such pollutants upon health and the atmosphere have been the subject of great public discussion. Undesirable pollutants result from combustion of carbonaceous fuel with combustion air that contains nitrogen. The combustion of conventional fuels with air in conventional engines and the relatively incomplete combustion of such fuels are the primary reasons for unsatisfactory levels of pollutants emitted by vehicles with internal combustion engines.